Apparatus for casting metal



Sept. 27, 1938, F. F. POLAND APPARATUS FOR CASTING METAL Original Filed April 12, 1935 Rmwy wivm Patented Sept. 27, 1938 2 1 7 UNITED STATES PATEN'ATOFZFICE ArPAnArUs ro ii llrm Marni. I

Application April 12, 1935, Serial No. 15,968

, Renewed December'13, 1937 I 4 Claims- (Cl. 2257.2)

In accordance with the present invention, there One of the factors influencing this friction is is provided an improved apparatus for producing the condition of the inner surfaces of the die,

5 characterized by its high density, freedom from face as is mechanically possible to obtain, 5

for the molten metal into a congealing chamber vides an improved process and apparatus in which 10 I 5 I inserted in the die or mold defining the congealing a tapered die, in which the metal becomes sepreservoir, the metal solidifying inthe die forming solidification occurs. a union with the plug, thereby enabling the with Another factor involved in thesuccessiul opera drawa] of the solidified metal from the die to be tion of continuous casting is the matter of'cooling started. Furthermore, the practice has been to the metal it being found in practice that most 20- of operation are maintained so that there is no operation of continuous casting lies in what ap- 25\ the solidified portions of the metal. low tensile strength at the high temperatures 30 It has been demonstrated in practice that the encountered during operation is considered I above outlined procedure is d1 0 o carry out ese factors are important considerations in metal being brought unduly low in the die defor the production of the required taper for the 35 fining he congelation chamber so that during bore, and t e imparting of a mlrror-like surface operation the metal will not solidify in the die, thereto, it must have high heat conductivity it but will run out therefrom in molten condition. should have a lubricating action on the metal Furthermore if sufiicient superheat is not presvarious materials may be used for die 40.- ent in the reservoir of molten metal tomaintain it has been found that graphite fulfills the above 40 the metal in the reservoir and in the congelation requirements ett r th n any h r di material above the die will take place, pluggingthe die combination, of the known proceses utilized'to 45.-from above with solid metal, thereby preventing reduce the porosity of the graphite, by means of th operation. which all porosity of the surface exposed to the p ed and since the metal, such as copper, has but a employed inthe casting operation. This softness low tensile strength at the temperatures encounsoon destroys the smoothness of the die surface tered during operation, the friction between the engaged by-the metal, particularly if the metal metal and the straight walls of the die tends to is not removed from the die in perfect axial aligncause fracturing of the newly solidified metal. ment with the bore of the die. "Also, the burning 55 First, by providing away of the die not only weakens the entire structure of the die and virtually prohibitively shortens its life in this manner, but by virtue of the fact that there is a space between the solidifled metal and the die surface, entry of air will very quickly produce irregular erosions of the die surface, thereby destroying the smoothness and a requirement for successful operation of this process.

The present invention has for its principal object the overcoming of the above mentioned diiilculties in the use of a graphite die, thereby rendering such a die practicable to use and retaining the desirable properties of graphite.

The attainment of this object is realized generally in two ways, according to this invention: a guide on the die in axial alignment with the bore of the die, through which guide the solidified metal is withdrawn; and second, by surrounding the die with a non-oxidizing atmosphere.

The accompanying drawing shows convenient means of accomplishing the objects of the invention, it being understood that various modifications of the specifically illustrated construction may be made without departing from the concept or scope of the invention.

In the drawing,

Fig. 1 represents a sectional elevation of an apparatus embracing the principles of the present invention.

Fig. 2 represents a sectional elevation of an assembled die constructed in accordance with this invention.

Fig. 3 is a sectional elevation of the die shown in F18. 2.

Fig. 4 is a plan view of the die of Fig. 3.

Fig. 5 is a sectional elevation of the guide for the metal being withdrawn this adapted tobe fitted over the outlet end-of the die.

Referring more particularly to the drawing. A

the metal be copper, for example.

Operatively associated with the reservoir A and adapted to receive molten metal therefrom is a die C, which is sealed into the reservoir A and which contains congealed or solidified metal I), which may be a starting rod used to close the outlet ,of the die C, and upon which congeals the adjacent molten metal at the interface 6, the location of which interface may vary with respect to the die, as will be hereinafter explained in more detail.

It will be observed that the die extends from the reservoir A for a rather substantial distance, water-jacket E positioned around the die and enclosing a substantial portion of the water being circulated continuby way of inlet 8 and outlet It. This water jacket abstracts heat from the metal, effecting congelation thereof, the heat being extracted predominantly from the metal through the die itself, and rapidly abstracting both latent and sensible heat from the metal interface 6. The location of this interface which represents the congelation point of the metal is maintained preferably below the level of the water-jacket.E, and in order to assure this a highly heat insulating sleeve F of a substantial thickness is snugly titted around the die 0 between the water jacket E and the metal reservoir A.

The reservoir A is positioned in a suitable heata supply of ing chamber maintained at suitable temperatures for maintaining the metal 3 thoroughly molten. the bottom of this heating chamber being shown K therein, in Jacket are enclosed.

As will be noted from Figs. 2 and 3, the die 0 has a uniformly-tapered bore l2 extending therethrough, in which bore the metal 8 congeals. The taper of the bore I2 is such that there is an open space between the congealed metal and the die, which space extends from the congealing zone of perience has shown that air in contact with the graphite die rapidly burns away from the outside and inside thereof, owing to the fact that the molten metal maintains the die at relatively high temperatures, notwithstanding the water jacket E, and that the die is rapidly consumed and destroyed.

In order to prevent this burning away of the sealed by a plate ll, which suitably cemented in position. The plate It provided with at least one inlet l8 and an outlet H, the inlet It being adapted to be connected to non-oxidizing gas (not shown) such as an ill ting gas line, or a supply of nitrogen gas, or carbon monoxide. or the like, whereby the space H between the die and solidified metal may be maintained flooded with such gas, so that continuously in inert gas, thereby preventing and prolonging indefinitely the far as concerns destruction of the die by burning.

It has been mentioned above also that it is withdraw the cast metal shapes or rod accurately axially from the die, as any deviation thereof and increased friction on the metal increasing thereby the chances of fracturing casting during its withdrawal from the die.

In order to reduce such tendencies, the die is guide positioned in true axial adapted to fit over the outlet end of the die C, which outlet end is externally threaded as 22 to receive the threads II of the it. The collar i8 is bored through as shown at 24, this bore being accurately made to be in axial alignment with the bore II of the C and collar the outside wall 21 of the die fitting snugly in the it, and with the end of the die abutting the annular shoulder 2! in the collar It.

The bore 24 in the collar it is straight-walled instead of being tapered as is the bore I! in the die, and the bore 2| is somewhat smaller in diameter than is the outlet of the bore l2. Thererore, as the rod is withdrawn from the die through the rolls 2! which are concentrically positioned relative to the axis of the die and collar, which rolls also guide the. rod, the collar It serves as a support for the rod and prevents any tendency of side pulling of the rod within the die, the rod being supported and guided so that it is withdrawn straight from the die. a

The surface of the bore N is highl'y'polished 7s molten metal and a. die operatively associated v a die connected to the reservoir for receiving 10 the die, cooling means for the die within the abling the maintenance ofanon-oxidizing atmos- 15 her enclosing the die fiile wit agaseous atmos- Apparatus for continuously casting metal 20 p ere inert to the die for preventing destructive comprising the combination with a reservoir for uming of the e. in ten metal commumcating with a. graphite die 

